The present invention relates to improvements in apparatus for testing block-shaped commodities, especially cigarette packs and like parallelepiped products. More particularly, the invention relates to improvements in apparatus which can be utilized with advantage for multiple testing of cigarette packs in cigarette packing machines.
It is well known to repeatedly test cigarette packs in a packing machine for the positioning, orientation, presence, integrity and/or other characteristics of their constituents (normally including an aluminum foil or tinfoil which constitutes the inner envelope, a paper layer or plastic layer which constitutes the outer envelope and a revenue or sealing label which is applied across the top of the pack. A cigarette packing machine is normally provided with a substantial number of testing stations which permit for monitoring of successive stages of the making of a soft or hard pack and whose sensors generate signals denoting the absence of a constituent and/or the detection of an unsatisfactory or improperly applied constituent. It is also known to monitor the condition of semifinished cigarette packs. German Offenlegungsschrift No. 32 19 001 of Sasib discloses an apparatus for transporting partly finished cigarette packs on an endless belt conveyor past a station at which successive packs are provided with labels. Such packs are thereupon transported past a monitoring station having means which detect the presence or absence of labels and generate signals for the ejection of each pack which failed to receive and/or retain a label. Thus, the apparatus of Sasib is designed to detect the presence or absence of a single defect so that a cigarette pack which has advanced beyond the monitoring station can exhibit an open seam on its outer envelope, an improperly folded or improperly adhering flap and/or other defects which remain undetected and are a cause of annoyance to the purchasers.
It happens again and again that a finished cigarette pack which has been monitored at several successive stations exhibits one or more defects which develop subsequent to testing of the pack and/or its constituents for such defects during certain stages of assembly of the pack. For example, the outer flap at the bottom of a so-called soft cigarette pack can properly adhere to the inner flap immediately downstream of the corresponding flap folding station but such outer flap is likely to open at a later stage, e.g., downstream of the labelling station. The corresponding packs remain undetected in presently known cigarette packing machines. Thus, it is desirable and advantageous to ascertain whether or not all constituents of a cigarette pack are or remain properly oriented and/or applied and are actually present upon completion of the last packing step, such as the application of revenue labels or sealing labels. As a rule, the defects most likely to be exhibited by a finished cigarette pack are the absence of one or more constituents (the foil, the outer layer and the label in the case of a soft pack), the location and/or orientation of the label, the configuration or outline of the pack, and the presence or absence of improperly bonded outer flaps. An outwardly extending (improperly bonded or unbonded) outer flap and/or a partially bonded label will change the configuration of the pack so that such configuration departs from the desired configuration and the pack cannot be readily introduced into a carton or the like.